Multicast traffic is typically a form of point to multi-point traffic, in which a user typically indicates an interest in receiving the traffic to a data network. The data network then may authorise the receipt of the traffic by the user equipment. Multicast traffic may be carried by many types of data network, including wireless networks, to provide services such as Multimedia Broadcast Multicast Service (MBMS). Wireless networks, in which a user equipment (UE) such as a mobile handset communicates via wireless links to a network of base stations or other wireless nodes connected to a telecommunications network, have undergone rapid development through a number of generations of radio access technology. The initial deployment of cellular systems using analogue modulation has been superseded by second generation (2G) digital cellular systems such as GSM (Global System for Mobile communications), typically using GERA (GSM Enhanced Data rates for GSM Evolution Radio Access) radio access technology, and these systems have themselves been replaced by or augmented by third generation (3G) digital systems such as UMTS (Universal Mobile Telecommunications System), using the UTRA (Universal Terrestrial Radio Access) radio access technology. Multimedia traffic may typically be carried by 2G and 3G systems.
Conventional macro-cellular wireless base stations may serve a relatively large area in which there are a large number of customer premises and users. In order to improve capacity and coverage, and to provide additional services to users, Femtocell systems have been developed, which typically employ wireless router nodes which are typically low power base stations which may be sited on a customer's premises, typically residential premises, with a typically small area of coverage. A femtocell base station may be self-installed by a customer, and it may typically be connected by backhaul through a telecommunication network to a public data network and to a mobile operator's core network. A femtocell base station operating using UTRA radio access technology in a UMTS system may be referred to as an HNB (Home Node B).
A femtocell may also be used to connect a user equipment to a local network, such as a residential network or enterprise network, using a service known as Local Internet Protocol Access (LIPA). Typically, the connection will not use a cellular wireless operator's core network. This may, for example, allow a user to download content from a local network and for example to connect to internet protocol enabled devices in the home.
Multimedia Broadcast Multicast Service (MBMS) is a service offered typically by a cellular wireless operator, by which content may be multicast to a group of users, the group typically having an multicast address. Membership of the group may typically be managed by a protocol known as Internet Group Management Protocol (IGMP) or Multicast Listener Discovery (MLD). Some types of femtocell base station, such as for example some types of Home Node B, may be not be enabled to offer MBMS.